Game-ready hair mesh technique like Zbrush's imm brushes or better
I want  to put this down for anyone who may read this answer for future reference. This was a breakthrough for me, and I hope it may be one for anyone who had similar problems to me.

If you 


Don't want to pay money for the hair tool addon, 
Don't want to pay money for Zbrush, 
Don't want to use a particle-based hair system for Blender,
Don't want as limited control over hair strands in Zbrush,
Or if you just want to stay in Blender, 


You may want to consider this following technique/addon. It's called Bevel Curve Tools, and it allows Blender users to use a hair-strip technique similar to Zbrush's imm brushes method while potentially being even better.

In addition to being free, this is supposedly better than Zbrush for controlling polycount for hair strips, easier to control tapering, generally less restricted than Zbrush's method. You can even duplicate a hair strand you may have made with its own beveling, which means you can easily manipulate it to add variation and change it to your liking. I'll be vague here since the video link below elaborates on it in much more detail if you're really interested. 

For further details, please consider checking out this Youtube video on how to use these addon. And of course, free downloads to the addons themselves are both on the video's description and will be at the bottom of this post in case you are confident with learning the tool on your own.

Good luck.

Github Bevel Curve Tools Download

Github 2 Blender Sculpt Tools (This is for extra features for Bevel Curve Tools, download this if you think you need it.)

How to use Bevel Curve Tools (Youtube Video)